The present invention relates to an apparatus for applying a protective spray coating to the white sidewall portion of a tire and, more particularly, to a device which minimizes the amount of overspray applied to portions of the tire surrounding the white sidewall.
The white sidewall portion of a tire is typically produced by rotating the tire, which is generally inflated, and engaging the sidewall portion of the tire with a rotating emery wheel in the area where the white sidewall is intended to be produced. The emery wheel grinds away the outer layer of black rubber to expose an underlying white layer of rubber wherein the exposed white rubber forms the white sidewall portion of the tire.
Subsequent to forming the white sidewall, it is necessary to protect the white surface from being marked or soiled during handling, such as might occur through contact with the black rubber portion of adjacent tires. The white sidewall portions of tires were formerly protected by wrapping the tires with a paper tape, and more recently have been protected by spraying a coating such as a water soluble soap, which is generally tinted blue or green, onto the white sidewall portion as the tire is rotated under a spray nozzle.
As illustrated in FIG. 4, the prior art machines which have been produced to spray a coating onto tire sidewalls have generally been designed to spray a variety of tire sizes 1, 2 that reach a tire spraying station at random. Unfortunately, such devices typically locate the spray nozzle 3 in a fixed position high enough to accommodate the largest and smallest diameter tires 1, 2 which are to be sprayed and disperse the spray in a diverging pattern in order to insure that the entire white sidewall portion 4 of any tire being sprayed is completely coated.
Such machines produce huge amounts of overspray which cause product appearance problems and which also are wasting the greater amount of paint being sprayed through the nozzle by directing them and applying them to portions of tires which do not require spray paint protection.
Therefore, an apparatus is needed for applying a protective coating to the white sidewall portions of tires wherein the device may randomly receive tires having different diameters and accurately limit the spraying of the protective coating to the white sidewall portion of the tires such that the amount of overspray beyond the white sidewall portion of the tires is minimized.